The current networking trend is to provide IP-based connections all the way to wired and wireless units. Some current objectives are to simplify the infrastructure, to support a wide range of applications, and to support diverse user demands on the communication service. To allow this, there is a need for scaleable solutions supporting service differentiation and dynamic resource management in IP networks.
One design trade-off made to enable interconnection was to support only best-effort service at the network level and rely on endpoint functionality to obtain various levels of service. Best-effort service provides adequate support for traditional data applications that can tolerate delay, loss and varying throughput along the path. However, in networks carrying high loads of traffic, this type of service is often inadequate for meeting the demands of applications that are more sensitive to packet loss and delay, e.g. telephony, video on demand, multimedia conferencing, etc.
Another trend is that the link technologies used in IP networks are becoming more heterogeneous ranging from fiber optic backbone links to various kinds of wired and wireless link technologies at the edges. Wireless access technologies may incur bottlenecks at the edges of the network. One trend is that wireless access technologies for global-area licensed-bands, e.g. GSM (Global System for Mobile communication), GPRS (General Packet Radio Services), UMTS (Universal Mobile Telecommunications System), are migrating from being purely connection-oriented towards applying IP all the way. These networks will be relatively resource-constrained compared with the wired IP networks. Hand-units in these networks traditionally provide real-time applications for human interaction, e.g. voice, but they are now migrating to providing multiple applications.
All these trends point towards the Internet becoming a ubiquitous multi-service network. Consequently, there are strong commercial reasons for network operators and equipment providers to offer Quality-of-Service (QoS) differentiation in IP networks. There will be a migration from the current version four of IP (IPv4) to version six (IPv6) to obtain more IP addresses and other additional functionality as well. The need for solutions providing QoS differentiation still prevails.
Qualitative services, better than best-effort services, can be provided by relying on Diffserv (Differentiated Services) support in routers and resource management mechanisms. Diffserv provides a moderate level of quality differentiation without strict guarantees. The distinctive technical characteristic is that QoS is not attained by reserving capacity for each individual flow or connection, but marking packets at the network boundaries. Thus, Diffserv refers to a simple service structure which provides quality differentiation mainly by means of packet marking. To provide quantitative service, resources must be dynamically administrated by resource management mechanisms and involve dynamic admission control to make sure that there are sufficient resources in the network to provide the services committed. There are specific requirements for resource management mechanisms. To provide service to end users, they must detect network resources and schedule them for the committed service at any granularity, e.g. for a port range, for aggregate traffic between a pair of subnets, etc. In order to keep both QoS and utilization high, aggregate level resource control is needed. The performance must also be sufficient to handle mobility and frequent hand-over.
IP RAN is a new radio access network platform based on IP transport technology. It supports interfaces towards core networks (CNs) and legacy RANs as well as legacy terminals. Furthermore, interfaces for GERAN (GPRS/EDGE RAN) and UTRAN (UMTS Terrestrial RAN) are supported.
Here, the term “legacy” is used to indicate those formats, applications, data or devices, which have been inherited from languages, platforms, and techniques earlier than the current technology. Typically, the challenge is to keep the legacy features or applications running while converting it to newer, more efficient features that make use of new technology and skills.
In IP RAN, most of the functions of centralized controllers, i.e. Radio Network Controllers (RNC) and Base Station Controllers (BSC) are moved to the base station. In particular, all the radio interface protocols are terminated in the base station. Thus, entities outside the base stations are needed to perform common configuration and some radio resource functions, or interworking with legacy functions, gateways to the CN, at least to support legacy CNs, and micro-mobility anchor points.
Furthermore, an IP Transport Resource Manager (ITRM) functionality is provided for managing IP resources in the bandwidth limited access part of the IP RAN by collecting load information of routers and by providing available bandwidth limits for the new IP Base Transceiver Stations (IP BTSs) and/or admission control entities. The major targets of the ITRM functionality are to provide overload protection functionality, to make QoS of IP RAN access transport less dependent on dimensioning and upgrading, and to increase robustness against link layer changes effecting transport capacity.
In order to perform the above-mentioned function, the ITRM functionality needs to know the network resources, e.g. IP topology and/or IP link capacities, of the managed part of the transport network. The managed part may be a subset of routing areas within an anonymous system. Especially, information about topology changes need to be received as fast as possible in order to minimize transport QoS problems for example during link failures.
Document U.S. Pat. No. 5,185,860 discloses mechanism of discovering network elements, or nodes connected to a computer network. Some nodes on the network, called discovery agents, convey knowledge of the existence of other nodes on the network. The network discovery system queries these agents and obtains the information they have about other nodes on the network. It then queries each of the other nodes obtained to determine if said node is also a discovery agent. In this manner, most of the nodes of a network can be discovered. The process of querying discovery agents to obtain a list of nodes known to the discovery agents is repeated at predetermined intervals to obtain information about nodes that are not always active. This known iterative method is continued as long as needed to get the entire topology and link information of the routing area. Hence, this procedure is slow and leads to an increased signaling load on the network links due to continuous queries.
Furthermore, a functionality has been proposed, which learns the network topology by listening to protocol messages and reports them to the ITRM functionality. However, this functionality will miss static route configurations which are hard to catch. Moreover, it requires complex router solutions and is strongly dependent on the used routing protocol.